Application of a Numerical Code Based on Smoothed Particle Hydrodynamics to Estimate Stresses in Granular Backfilled Openings

moothed particle hydrodynamics (SPH) method has been used in this thesis to study the backfilling process of a backfilled rock stope. The SPH method has the advantage of discretizing the backfill material into particles interacting with each other, thus simulating the granular particles of the backfill and making it possible to reproduce the backfilling process. Three models were constructed using Abaqus software (2020) to study the effect of the backfilling process and deposition mode. The first model is an SPH model with a wished-in-place backfill representing the backfill material already in place in the rock stope. The second model is a FEM model with also a wished-in-place backfill: this model will serve as a comparison model because it represents the simulations generally carried out for this type of problems. The third model is an SPH analysis representing a uniform, continuous and progressive backfilling process. This model is composed of two backfilling modes: the first one taking place along the longitudinal direction of the stope and the second one along the transversal direction. Several backfilling velocities were also considered in the analyses. The results of these models were compared with each other and with the analytical results developed by Li and Aubertin (2008). The results of these simulations reveal that the contact pressure (CPRESS) distribution at the end of the backfilling process depends on several factors and a new state of interfacial contact stresses, and a dense gathering of particles can occur due to a rearrangement of the particles. In general, and for a specific initial mesh density, it is expected that values of CPRESSs increase when the initial mesh density decrease. It is also expected that values of CPRESSs increase when the backfilling velocity increase and values of CPRESSs are higher for a backfilling process in the transversal direction. For the backfilling process in the transversal direction, an arching effect is observed and is conditioned by the location of the vertical stopes where a stress transfer between the stiff backfill material and the stiffer surrounding rock mass due to friction at the interface of the two materials reduces the pressure and the stress near the stope-walls.